レストランの予約は何時？って英語でなんて言うの？

In this example - "What time is our dinner reservation?" the word dinner is interchangeable with lunch or breakfast. It is a question that requests a specific answer - the time of the booking. I would always say 'the' rather than 'a'. For example: What time did you book 'a' table for? What time did you book 'the' table for? If you were asking "Did you book 'a' table at Maccas?" this may be a reminder to make sure the person had booked a table at a specific place.

What time is the table booked for? - This phrase is more common as it is casual, you can use this with friends & family. e.g. Did you book the table? What time is it booked for? What time are we going/meeting? - If you already know the venue/restaurant & you are with the people you can ask "What time are we going?" if you are away from these people you and you plan on meeting them there, you can ask "What time are we meeting?" When is the reservation? - This is a bit more formal and is asking for a detailed response e.g. Mike: "When is the reservation?" Carl: "The reservation is at 5pm on Thursday at the Peeking restaurant down town."

*What time is the dinner?- Since this is your boyfriend there is no need to be formal. For example: You: What time is the dinner? Him: I made a reservation for 9pm. *What time should I be ready?- You can use this sentence if he is coming to pick you up. For example: You: What time should I be ready? Him: Our dinner is at 9pm so I will come pick you at 8pm.

You would use "the" before reservation because you are speaking about a specific reservation. Whereas "a" would be used to talk in general terms. "What time did you reserve the table for?" can be used to ask about a restaurant reservation time.

The use of articles such as "a" and "the" make nouns specific or nonspecific. Using "a" would be any table at all. Using "the" would mean a particular type. In this case, "the" would be the correct article as it is a specific table for you and your boyfriend.

When talking about something specific that you and your boyfriend both know, we use "the" instead of "a" as you both know it's the same restaurant and the same reservation. "A" is used with something that isn't specific, when you don't know which restaurant. In this situation, you can say "our" instead of "the" or "a" as you are referring to your own reservation and not someone else's. In restaurants, people use "reserve a table" and not "book a table". Hope this helps!

You should use 'the' when talking about a table that you have booked. The table is unique and it is also yours - two reasons to use 'the' as opposed to 'a'.